Tall Fescue: A Problematic Pasture Grass

Tall fescue

Tall fescue is a pasture grass that is relatively easy to identify late in the season – just look for the grass that your animals have refused all season. Typically livestock will avoid tall fescue if given other options. That is because this tall bunch grass is quite unpalatable. The leaves, which are quite broad, are very coarse and leathery. The edges can be quite sharp as well. Rub a leaf between your fingers and you’ll see why your animals would choose not to eat it.

Besides the physical attributes that make it unappetizing, tall fescue can be toxic as pasture, hay or haylage due to endophyte alkaloids. Endophytes are fungi which live within the plant and produce alkaloid chemicals. Fescue toxicosis can result in various production-related issues ranging from foot problems to reproduction issues. There are endophyte-free varieties of tall fescue, but these have alkaloids as well, and although less toxic than their endophyte-infected counterparts, they still upset rumen function and therefore reduce animal performance. Toxicity is a measure of the overall percentage of tall fescue plants in the pasture and decreases if animals are in a diverse sward with many other grass and legume species.

Some producers have noticed this past year more tall fescue in their pastures than ever before. What is going on? The reason tall fescue is the grass of choice in the Southeast is that it is very drought resistant. It will grow when nothing else will. In a dry year like 2012, when our cool-season grasses went dormant in the heat of summer with little to no rain, tall fescue will take the opportunity to grow and spread.

Some tall fescue is seeded intentionally. For example, when ditches and roadsides are seeded with ‘conservation mixes’, these typically contain tall fescue as it will establish with little effort. The seed then spreads into neighboring fields and pastures. Interestingly, many commercial pasture seed mixes on the market also contain tall fescue. This is a sign that the seed mix was developed for other regions of the country where the climate is not conducive to the cool-season grasses we can grow so well here. We have so many better options for cool-season grasses such as bluegrass, ryegrass, and orchardgrass, to name a few, that tall fescue is a plant best to avoid.

If you are finding that tall fescue is spreading and becoming a problem what do you do? Unfortunately, tall fescue is hard to get rid of without an herbicide, so if you are an organic producer it will depend on how much of a problem it is. One option is to seed plants with high tannin content such as forage chicory or birdsfoot trefoil. When animals eat both the tannins and the alkaloids together, the tannins bind the alkaloids and reduce toxicity problems. For a real problem stand, plowing and tilling would kill most of the existing plants. Following with an annual crop such as a small grain, and then seeding down to a pasture/hay crop would increase the chances of eliminating the tall fescue plants.

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